DE68923570T2

DE68923570T2 - Photographic light-sensitive material with a polyester base.

Info

Publication number: DE68923570T2
Application number: DE1989623570
Authority: DE
Inventors: Kenji Kida; Seimi Satake; Yoshihiko Shibahara; Toshiaki Ueda
Original assignee: Toray Industries Inc; Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp; Toray Industries Inc
Priority date: 1988-03-25
Filing date: 1989-03-23
Publication date: 1996-04-11
Anticipated expiration: 2009-03-24
Also published as: DE68923570D1; CA1338693C; EP0334367A2; EP0334367B1; AU3163989A; AU617160B2; JPH01244446A; EP0334367A3; JP2565370B2

Description

FIELD OF INVENTION

The present invention relates to a photographic light-sensitive material, particularly to a photographic light-sensitive material comprising a support made of a polyester material which has light transmittance and excellent curl-erasing properties after development processing, which properties are independent of the environment with the passage of time.

BACKGROUND OF THE INVENTION

Photographic photosensitive materials are generally prepared by coating at least one photographic photosensitive layer on a plastic film support. As the plastic film, fiber type polymers represented by triacetyl cellulose (hereinafter abbreviated as "TAC") and polyester type polymers represented by polyethylene terephthalate (hereinafter abbreviated as "PET") are generally used.

PET has been traditionally considered as a substitute for TAC due to its excellent productivity, mechanical strength and dimensional stability. However, in the rolled state, which is widely used for photographic photosensitive materials, PET has a strong tendency to retain the curl from the rolled state, and therefore its handling properties after development processing are so poor that the scope of its application is limited, despite the excellent properties described above.

Photographic light-sensitive materials generally include sheet types such as X-ray film, plate-making film, cut film, and roll film. Typical examples are color or black-and-white negative films of 35 mm or less width stored in a cartridge and designed to be inserted into ordinary cameras for photographing.

On the other hand, the most important aspect of the TAC films as photographic supports mainly used for roll films is that they are optically non-anisotropic and have high light transmittance. In addition, they have another excellent aspect. That is, they have excellent curl cancellation properties after development processing. Since TAC films have comparatively high water-absorbing properties for plastic films due to their molecular structure, the molecular chain is fluidized after absorbing water during development processing, and the tendency to curl up, which is imparted by leaving it in a rolled state as a roll film for a long time, is canceled as a result of the rearrangement of the molecular chain which is fixed after being rolled up for a long time. However, photographic light-sensitive materials using films that do not exhibit the curling tendency canceling properties of TAC films have problems such as the formation of cracks, blurring and squeaking after further transport in the rolled state, for example, in the printing stage when forming an image on a photographic printing paper after development.

Recently, the acceleration of film advancement after photographing, the extension of photographic amplification and the reduction in size of photographic cameras have become remarkable. In such situations, supports for photographic photosensitive materials are required to have sufficient strength, dimensional stability and reduction in film thickness to meet these new advances.

However, the TAC described above, when formed into a film, creates only a fragile film due to its rigid molecular structure and cannot be used for these advances. In addition, PET films cannot be used as roll films where the curling tendency is problematic despite their excellent mechanical properties. Therefore, a significant improvement of PET films is highly desired.

US-A-4,217,441 and 4,241,170 disclose that a PET film modified by reacting with a certain specific compound is used as a support for a photographic material. In this case, however, problems arise in that the film becomes whitened during processing and with the passage of time and the light transmittance of the film is reduced. Therefore, further improvements in the light transmittance of the film have been desired.

US-A-3 052 543 discloses a photographic material comprising a specific film support having disposed thereon at least one layer of a copolymer of vinylidene chloride, an acrylic acid ester and itaconic acid and at least one layer of a water-permeable colloid having protective colloid properties. The film support comprises a polyester film formed by reacting a specific dicarboxylic acid (or a derivative thereof) with a specific dihydroxy compound and a specific metal sulfonate.

CONTENT OF THE INVENTION

The object of the invention is therefore to provide a photographic light-sensitive material comprising a polyester film support having high transparency and excellent mechanical properties and excellent curl-erasing properties after development processing.

The object of the invention can be achieved by a photographic light-sensitive material comprising a polyester film support having at least one light-sensitive silver halide emulsion layer provided thereon, the polyester film having a fog of up to 3%, a water content of 0.5% by weight to 5.0% by weight, a curl erasure ratio of up to 50% or more, and as predominant components a terephthalic acid component and a glycol component, the polyester film further comprising an aliphatic dicarboxylic acid component having 4 to 20 carbon atoms as a copolymerization component in an amount of 3 to 25 mol% based on the terephthalic acid component, wherein the fog is measured in accordance with ASTM D1003-52 after heat-treating the film at a temperature of 150°C for ten minutes, and the water content is measured after first adjusting the film to humidity under conditions of 23°C and 30% RH for 3 hours, and next exposing the film to distilled water at 23ºC for 15 minutes, and then the water content is measured using a micro moisture meter at a drying temperature of 150 C, and the curl-quenching ratio is measured after first immersing the film in distilled water at 40ºC for 15 minutes and then drying it for 3 minutes in air at 55ºC held in a thermostatic chamber using a load of 50 g.

DETAILED DESCRIPTION OF THE INVENTION

In the invention, the water content of the polyester film is measured by wetting the film under conditions of 23ºC, 30% RH and 3 hours, immersing the film in distilled water of 23ºC for 15 minutes and then using a micro moisture meter (e.g., Model CA-02, manufactured by Mitsubishi Chemical Industries, Ltd.) at a drying temperature of 150ºC.

In the invention, the term "polyester" means a polyester containing, as main components, a terephthalic acid component and a glycol. Examples of the terephthalic acid component include terephthalic acid and isophthalic acid, and examples of the glycol include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, 1,4-cyclohexanediol and diethylene glycol. Among the polyester films comprising these components, polyethylene terephthalate (PET) is the most convenient from the viewpoint of accessibility, and therefore the following descriptions refer to PET.

The copolymerized PET films preferably used in the invention include copolymerized PET films containing a metal sulfonate-containing aromatic dicarboxylic acid component as a copolymerizable component.

Specific examples of the metal sulfonate-containing aromatic dicarboxylic acid include 5-sodium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 4-sodium sulfophthalic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid, and compounds in which sodium in the above-described compounds is replaced by another metal (e.g., potassium or lithium). The copolymerization ratio of the metal sulfonate-containing aromatic dicarboxylic acid component is preferably about 2 to 15 mol%, in particular about 4 to 10 mol%, based on the aromatic dibasic acid component, for example the terephthalic acid component.

For copolymerization, an aliphatic dicarboxylic acid component containing 4 to 20 carbon atoms is used for the copolymerized PET film from the viewpoint of transparency, particularly suppression of whitening and enhancement of bending resistance of the copolymerized PET film.

Specific examples of the aliphatic dicarboxylic acid component containing 4 to 20 carbon atoms are succinic acid, adipic acid and sebacic acid, with adipic acid being particularly preferred. The copolymerization ratio of the aliphatic dicarboxylic acid component containing 4 to 20 carbon atoms is 3 to 25 mol%, preferably 5 to 20 mol%, based on the terephthalic acid component.

In addition, in the polyester film of the invention, other acid components or glycol components may be copolymerized in a small proportion so that the transparency and mechanical properties are not impaired. For example, polyalkylene glycol, particularly polyethylene glycol may be copolymerized in a proportion of 0 to 10% by weight based on the amount of polyester produced. The polyalkylene glycols to be used for the purposes described above preferably have a molecular weight of about 600 to 10,000. The polyester film of the invention preferably comprises a polymer having an inherent viscosity of about 0.5 to 0.9 as measured in o-chlorophenol at 25°C.

Furthermore, various additives can be incorporated into the polyester film of the invention. When using a polyester film as a support for a photographic light-sensitive material, one of the problems is light piping due to the high refractive index of the support. As photographic supports, triacetyl cellulose (TAC) and polyester type polymers represented by PET are generally used. One of the biggest optical differences between TAC and PET is the refractive index. PET has a refractive index of about 1.6, while TAC has a smaller refractive index of 1.5. On the other hand, gelatin is mainly used in the undercoat layer, and a photographic emulsion layer has a refractive index of 1.50 to 1.55. Therefore, the ratio of the refractive index of gelatin to that of PET is 1.5/1.6, which is smaller than 1. Therefore, if light passes through a film edge, the light is easily reflected at the interface between the base and the emulsion layer, so that polyester type films easily undergo what is known as light piping.

As a technique for preventing the phenomenon of light leakage, for example, a technique for incorporating inert inorganic particles or the like into the films and a technique for adding a dye are known. The technique for preventing light leakage used in the invention is the addition of a dye, which does not seriously increase the film fog.

Dyes used for coloring the film are not particularly limited, but the tone is preferably gray in view of the general properties of photosensitive materials. Dyes to be used are preferably those which have excellent heat resistance in a temperature range in which the polyester film is formed and have excellent compatibility with the polyester.

From the point of view described above, dyes that are commercially available can be used as dyes for Polyesters such as Diaresin (manufactured by Mitsubishi Chemical Industries, Ltd.) and Kayaset (manufactured by Nippon Kayaku KK) can be used to achieve the above-described objective.

Regarding the coloring density, at least a color density in the visible region of 0.01 as measured by a color densitometer (manufactured by Machbeth Co.) is necessary, with 0.03 or higher being preferable.

If the application requires, sliding properties can be imparted to the polyester film in accordance with the invention. There are no restrictions on the techniques for imparting sliding properties, but a technique of kneading an inert inorganic compound into the film or a technique of coating a surfactant is generally used.

The inert inorganic particles are SiO2, TiO2, BASO4, CaCO3, talc and kaolin. In addition, a technique of adding the inert particles to the polyester-synthesizing reaction system to impart sliding properties by the external particle system and a technique of precipitating a catalyst or the like added after the polymerization reaction of the polyester to impart sliding properties by the internal particle system can also be employed.

Since transparency is an important factor for a support for photographic light-sensitive materials, SiO₂ having a comparatively corresponding refractive index such as the polyester film is preferably selected as the external particle system, or an internal particle system capable of precipitating particles having a comparatively small particle size is preferably selected as the internal particle system. which, however, does not limit the technique for imparting sliding properties.

Furthermore, in the case of imparting slip properties by a kneading technique, it is also preferable to laminate a layer which imparts transparency to the film. As the technique for the lamination, a coextrusion method using a plurality of extruders and a feed block or a multi-distribution die is given.

In the invention, precipitation of a low-polymerized product sometimes takes place after the thermal treatment for forming the undercoat layer in a small copolymerization ratio. In such a situation, it is possible to laminate an ordinary polyester layer on at least one side of the support. For this lamination, the coextrusion method is an effective technique used.

Starting polymers for the copolymerized PET film of the present invention can be synthesized according to conventionally known methods for producing polyesters. For example, copolymerized PET can be obtained by directly esterifying a dibasic acid component and a glycol component at a temperature of 200°C to 270°C and removing a theoretical amount of water, or by using a lower alkyl ester as a dibasic acid component and conducting an ester exchange reaction between the dibasic acid component and the glycol component at a temperature of 100°C to 250°C and removing a theoretical amount of a lower alcohol to obtain a glycol ester of the dibasic acid or a low molecular weight polymer. Then, the obtained product is heated at a temperature of 200°C to 300°C under a gradually reduced pressure to about 133 Pa (1 Torr) to remove the excess glycol component. A catalyst for an ester exchange reaction or a A catalyst for a polymerization reaction may be used as described in US-A-2,647,885 and 2,739,957, GB-B-742,196 and 770,531, or a stabilizer for heat resistance described in the above patents may be added.

The copolymerized PET thus obtained is generally granulated, dried, melt-extruded to form an unstretched film sheet, then biaxially stretched and heat-treated to obtain the final film.

Biaxial stretching may be carried out successively in the order of the longitudinal direction and the transverse direction or in the reverse order, or simultaneously in both directions. The stretching ratio is not particularly limited, but is generally 2.0 to 5.0 times. Post-stretching in the transverse or longitudinal direction may be carried out after stretching in the transverse or longitudinal direction.

As the drying technique used before melt extrusion in the invention, a vacuum drying technique or a dehumidification drying technique is preferred.

The stretching temperatures in the invention are desirably 70 to 100°C after longitudinal stretching and 80 to 160°C after transverse stretching.

The temperatures for heat fixing are 150 to 210ºC, particularly preferably 60 to 200ºC.

The thickness of the copolymerized PET film to be used in the invention can be appropriately determined depending on the end use of the photographic film, and is preferably 25 to 250 µm, particularly 40 to 150 µm.

The copolymerization formulation in the invention does not impair the excellent transparency and mechanical strength which PET basically possesses, and provides a film haze of up to 3%, a breaking strength of 8 to 25 kg/mm², an initial modulus of 200 to 500 g/mm² and a tear strength of not less than 30 g at a thickness of 120 µm. If the strength is less than the above range, the excellent mechanical strength which PET basically possesses is deteriorated, and hence the superiority over TAC is lost.

In the invention, the transparency, breaking strength, initial modulus and tear strength are measured as follows.

transparency

The fog of a film is measured according to ASTM D1003-52 after heat treating the film at a temperature of 150ºC for 10 minutes. This heat treatment is generally applied to a film support in the step of coating the photographic layer.

Breaking strength and initial modulus

A specimen of 10 mm width and 100 mm length is subjected to measurement according to JIS Z1702-1976 using a tensile rate of 300 mm/min to measure the ultimate strength and 20 mm/min to measure the initial modulus.

The polyester film support to be used in the invention has excellent properties for erasing the curling tendency after development processing (hereinafter referred to as curl erasing ratio). In the invention the curl quenching ratio, measured by the following method, is 50% or more, preferably 80% or more.

Measurement of the curl erasure ratio

A sample of size 12 cm x 35 cm is wound around a core of 10 mm diameter and left under the conditions of 60 C x 30% RH x 72 h. It is then unwound from the core, immersed in distilled water at 40ºC for 15 minutes and dried for 3 minutes in a thermostatic air chamber at 55ºC while applying a load of 50 g. The length of the sample thus treated is measured in a vertically suspended state to evaluate the degree of recovery of the original length of 12 cm.

The copolymerized PET film to be used in the invention has better adhesiveness to various coating layers such as emulsion layers than conventional PET films. The polyester film to be used in the invention may be subjected to corona discharge treatment, chemical solution treatment or flame treatment in advance, if necessary. Among these surface treatments, corona discharge treatment is most preferably used in the invention because it causes little precipitation of a low polymerized product on the film surface.

The polyester support to be used in the invention preferably has a subbing layer for enhancing adhesion to a photographic layer such as a light-sensitive layer to be coated thereon.

As the underlayer, an underlayer using a polymer latex composed of a styrene-butadiene type copolymer or a vinylidene chloride copolymer, and an undercoat layer using a hydrophilic binder such as gelatin.

Preferably, as the subbing layer in the invention, a subbing layer using a hydrophilic binder is used.

As the hydrophilic binder to be used in the invention, there can be mentioned, for example, water-soluble polymers, cellulose esters, latex polymers and water-soluble polyesters. The water-soluble polymers include gelatin, gelatin derivatives, casein, agar-agar, sodium alginate, starch, polyvinyl alcohol, polyacrylic acid copolymers and maleic anhydride copolymers, and the cellulose esters include carboxymethyl cellulose and hydroxyethyl cellulose. The latex polymers include vinyl chloride-containing copolymers, vinylidene chloride-containing copolymers, acrylic ester-containing copolymers, vinyl acetate-containing copolymers and butadiene-containing copolymers. Of these, gelatin is most preferred.

As compounds capable of swelling the carrier to be used in the invention, there are mentioned, for example, resorcinol, chlororesorcinol, methylresorcinol, o-cresol, m-cresol, p-cresol, phenol, o-chlorophenol, p-chlorophenol, dichlorophenol, trichlorophenol, monochloroacetic acid, dichloroacetic acid, trifluoroacetic acid and chloral hydrate. Among these, resorcinol and p-chlorophenol are preferred.

Various gelatin hardeners can be used in the undercoat layer of the invention.

Examples of gelatin hardening agents include chromium salts, such as chromium double salt (chromium alum), aldehydes (such as formaldehyde and glutaraldehyde), isocyanates, active halogen compounds (such as 2,4-dichloro-6-hydroxy-s-triazine) and epoichlorohydrin resin.

The undercoat layer to be used in the invention may contain fine particles of an inorganic substance such as SiO₂ or TiO₂ or fine particles (1 to 10 µm) of polymethyl methacrylate copolymer as a matting agent.

The undercoat layer to be used in the invention can be coated according to publicly known coating methods such as a dip coating method, air knife coating method, curtain coating method, wire rod coating method, gravure coating method or extrusion coating method.

The photosensitive material of the present invention may have light-insensitive layers such as an anti-halation layer, an intermediate layer, a back layer and a surface protective layer in addition to the photosensitive layers.

The binder for the backing layer may be a hydrophobic polymer or may be a hydrophilic polymer as used for the undercoat layer.

The back layer of the photosensitive material in accordance with the invention may contain an antistatic agent, a lubricant, a matting agent, a surfactant and a dye. The antistatic agents to be used in the invention are not particularly limited and are therefore, for example, high molecular weight anionic electrolytes such as high molecular weight polymers containing carboxylic acid groups, carboxylic acid salt groups or sulfonic acid groups (for example, high polymers as described in JP-A-48-22017 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application"), JP-B-46-24159 (the term "JP-B" as used herein refers to an "examined Japanese Patent Publication"), JP-A-51-30725, JP-A-51-129216, JP-A-55-95942 and cationic high polymers as described in JP-A-49-121523, JP-A-48-91165, JP-B-49-24582, etc. Ionic surfactants also include anionic and cationic surfactants and are exemplified by those described in JP-A-49-85826, JP-A-49-33630, US-A-2 992 108 and 3 206 312, JP-A-48-87826, JP-B-49-11567, JP-B-49-112568 and JP-A-55-70837.

The most preferred antistatic agents for the back layer of the invention are fine particles of at least one crystalline metal oxide selected from ZnO, TiO₂, SnO₂, Al₂O₃, In₂O₃, SiO₂, MgO, BaO and MoO₃, or a composite oxide thereof.

Fine particles of the conductive crystalline oxides or their composite oxides to be used in the invention have a volume resistivity of up to 10⁷ Ω·cm, preferably up to 10⁵ Ω·cm, and a particle size of from 0.01 to 0.7 µm, particularly preferably from 0.02 to 0.5 µm.

Methods for producing the fine particles of the conductive crystalline metal oxides or their composite oxides to be used in the invention are described in detail in JP-A-56-143430 (corresponding to US-A-4,495,276) and JP-A-60-258541. They can be easily produced by first preparing fine particles of the metal oxide by sintering and heat-treating the particles in the presence of a different atom capable of improving the conductivity, and secondly, by allowing a different metal capable of improving the conductivity to coexist until the fine metal oxide particles are prepared by sintering; and thirdly, by reducing the oxygen concentration of the atmosphere after the fine metal oxide particles are prepared by sintering to thereby introduce oxygen deficiency.

Examples of different atoms are: Al, In for ZnO; Nb, Ta for TiO₂; and Sb, Nb, halogen atoms for SnO₂. The different atom is added in an amount of preferably 0.01 to 30 mol%, especially 0.1 to 10 mol%.

Photographic layers for the photographic light-sensitive material of the present invention are described below. The most preferable examples of the photographic light-sensitive material of the present invention are silver halide photographic light-sensitive materials, which are represented by silver halide color negative films, color positive films, color reversal films and black-and-white negative films.

The photographic emulsion to be used in the invention can be prepared by the methods described in P. Glafkides, Chimie et Physique Photographique (Paul Montel, 1967), GF Duffin, Photographic Emulsion Chemistry (The Focal Press, 1966), VL Zelikman et al., Making and Coating Photographic Emulsion (The Focal Press, 1964). That is, any acidic method, neutral method and ammonia method can be used. For reacting a soluble silver salt with a soluble halide salt, any of one side mixing, simultaneous mixing and combinations thereof can be used.

A method of forming silver halide grains in the presence of excess silver ions (called reverse mixing method) can also be used. As one type of simultaneous mixing, a method called controlled double jet method in which the pag in a liquid phase in which the silver halide is formed is kept constant can be used. This method provides a silver halide emulsion containing silver halide grains of regular crystal form with approximately uniform grain size.

Two or more silver halide emulsions which have been prepared separately may be mixed for use.

During the formation or physical ripening of silver halide grains, cadmium salts, zinc salts, lead salts, thallium salts, iridium salts or their complex salts, rhodium salts or their complex salts, iron salts or their complex salts may coexist.

As a binder or protective colloid for the photographic emulsions, gelatin is advantageously used. However, other hydrophilic colloids can also be used. For example, proteins such as gelatin derivatives, graft polymers between gelatin and other high molecular weight polymers, albumin, casein; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, cellulose sulfate; sugar derivatives such as sodium alginate, starch derivative; and various synthetic macromolecular substances such as homopolymers or copolymers (e.g. polyvinyl alcohol, partially acetalized polyvinyl alcohol, poly-N-pyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole) can also be used.

As the gelatin, there can be used acid-treated gelatin or enzyme-treated gelatin as described in Bull. Soc. Sci. Phot. Japan, No. 16, p. 30 (1966), as well as lime-treated gelatin and a gelatin hydrolysate or an enzyme-degraded product. As the gelatin derivatives, there can be used those obtained by reacting gelatin with various compounds such as acid halides, acid anhydrides, isocyanates, bromoacetic acid, alkanesulfones, vinylsulfonamides, maleimide compounds, polyalkylene oxides, epoxy compounds or the like. Specific examples thereof are described in US-A-2,614,928, 3,123,945, 3,186,846, 3,312,553, GB-B-861,414, 1 033 189 and 1 005 784, JP-B-42-26845.

As the aforementioned gelatin graft polymers, products prepared by grafting a homo- or copolymer of a vinyl monomer such as acrylic acid, methacrylic acid, esters or amides thereof, acrylonitrile, styrene onto gelatin can be used. In particular, graft polymers between gelatin and a polymer having some compatibility with gelatin such as a polymer of acrylic acid, methacrylic acid, acrylamide, methacrylamide, hydroxyalkyl methacrylate are preferred.

Examples are described in US-A-2 763 625, 2 831 767, 2 956 884.

Typical synthetic substances with high molecular weight are those described, for example, in DE-A-2 312 708, US-A-3 620 751 and 3 879 205 and JP-B-43-7561.

For the photographic emulsion to be used in the invention, various compounds for preventing fog or for stabilizing the photographic properties during the steps of manufacturing, storing or photographic processing of the light-sensitive material may be incorporated. That is, many compounds known as antifogging agents or stabilizing agents such as azoles (e.g. benzothiazolium salts, nitroindazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (especially 1-phenyl-5-mercaptotetrazole); mercaptopyrimidines; mercaptotriazines; thioketo compounds (e.g. oxazolinethione); azaindenes (e.g. triazaindenes, tetraazaindenes (especially 4-hydroxy-substituted 1,3,3a,7-tetraazaindenes); pentaazaindenes); benzenethiosulfonic acid, benzenesulfinic acid; benzenesulfonamide; can be added. For example, those which are described in US-A-3 954 474 and 3 982 947, JP-B-52-28660.

The photographic emulsion layer of the photographic light-sensitive material of the present invention may contain a polyalkylene oxide or its ether, ester or amine derivative, a thioether compound, a thiomorpholine, a quaternary ammonium salt compound, a urethane derivative, a urea derivative, an imidazole derivative, a 3-pyrazolidone, etc. for the purpose of enhancing sensitivity or contrast or for accelerating development. For example, those described in US-A-2,400,532, 2,423,549, 2,716,062, 3,617,280, 3,772,021 and 3,808,003, GB-B-1,488,991 can be used.

The photographic emulsion used in the invention may be spectrally sensitized with methine dyes. Suitable dyes include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styrene dyes and hemioxonol dyes. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes and complex merocyanine dyes. These dyes may contain, as the basic heterocyclic nucleus, any of the nuclei commonly used for cyanine dyes.

That is, it may contain a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus, a pyridine nucleus; nuclei in which an alicyclic hydrocarbon ring or rings are fused to these nuclei, and nuclei in which an aromatic hydrocarbon ring or rings are fused to these nuclei, i.e. an indolenine nucleus, a benzindolenine nucleus, an indole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzothiazole nucleus, a Naphthothiazole nucleus, a benzoselenazole nucleus, a benzimidazole nucleus and a quinoline nucleus. These nuclei can be substituted on the carbon atom or atoms thereof.

Merocyanine dyes or complex merocyanine dyes contain as the ketomethylene structure-containing core a 5- or 6-membered heterocyclic core, such as a pyrazolin-5-one core, a thihydantoin core, a 2-thiooxazolidine-2,4-dione core, a thiazolidine-2,4-dione core, a rhodanine core and a thiobarbituric acid core.

Useful sensitizing dyes are described, for example, in DE-C-929 080, US-A-2 231 658, 2 493 748, 2 503 776, 2 519 001, 2 912 329, 3 656 959, 3 672 897, 3 594 217, 4 025 349, 4 046 572, GB-B-1 242 588, JP-B-44-14030 and JP-B-52-24844.

These sensitizing dyes may be used alone or in combination. Combinations of sensitizing dyes are often used to achieve supersensitization in particular. Typical examples thereof are described in US-A-2,688,545, 2,977,229, 3,397,060, 3,522,052, 428, 3,703,377, 3,769,301, 3,814,609, 3,837,862, 4,026,707, GB-B-1,344,281 and 1,507,803, JP-B-43-4936, JP-B-53-12375, JP-A-52-110618 and JP-A-52-109925.

Dyes which do not themselves exhibit a spectral sensitizing effect or materials which do not absorb visible light to a large extent but which exhibit supersensitivity can be incorporated into the emulsion together with the sensitizing dyes. For example, aminostilbenes substituted by a nitrogen-containing heterocyclic group (for example, those described in US-A-2,933,390 and 3,635,721), aromatic organic acid-formaldehyde condensates (for example, those described in US-A-3,743,510 described), cadmium salts, azaindene compounds, etc. can be incorporated. Combinations described in US-A-3,615,613, 3,615,641, 3,617,295, 3,635,721 are particularly useful.

The light-sensitive material of the present invention may contain water-soluble dyes as filter dyes or for various purposes such as antiirradiation. Such dyes include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes and azo dyes. Among these, oxonol dyes, hemioxonol dyes and merocyanine dyes are useful. Specific examples of useful dyes are described in GB-B-584 609 and 1 177 429, JP-A-48-85130, JP-A-49-99620, JP-A-49-114420, JP-A-52-108115, US-A-2 274 782, 2 533 472, 2 956 879, 3 148 187, 3 177 078, 3 247 127, 3 540 88?, 3 575 704, 3 653 905, 3 718 472, 4 071 312 and 4 070 352.

In the light-sensitive material obtained according to the invention, photographic emulsion layers and other hydrophilic colloidal layers may contain fluorescent brightening agents of stilbenes, triazines, oxazoles, coumarins, etc. These agents may be of water-soluble type or water-insoluble type, the latter being used in the form of a dispersion. Specific examples of fluorescent brightening agents are described in US-A-2,632,701, 3,269,840, 3,359,102, GB-B-852,075 and 1,319,763.

In carrying out the invention, the following known dye stabilizers can be used in combination. The color image stabilizing agents to be used in the invention can be used alone or in combination of two or more. The known dye stabilizers include, for example, hydroquinone derivatives described in US-A-2 360 290, 2 418 613, 2 675 314, 2 701 197, 2 704 713, 2 728 659, 2 732 300, 2 735 765, 2 710 801, 2,816,028, GB-B-1,363,921; gallic acid derivatives described in US-A-3,457,079, 3,069,262; p-alkoxyphenols described in US-A-2,735,765 and 3,698,909, JP-B-49-20977, JP-B-52-6623; p-hydroxyphenols described in US-A-3,432,300, 3,573,050, 3,574,627, 3,764,337, JP-A-52-35633, JP-A-52-14734, JP-A-52-152225; Bisphenols, described in US-A-3,700,455.

The light-sensitive material produced by the invention may contain hydroquinone derivatives, aminophenol derivatives, gallic acid derivatives, ascorbic acid derivatives as color fog preventing agents. Specific examples are described in US-A- 2 360 290, 2 336 327, 2 403 721, 2 418 613, 2 675 314, 2 701 197, 2 704 713, 2 728 659, 2 732 300, 2 735 765, JP-A-50-92988, JP-A-50-92989, JP-A-50-93928, JP-A-50-110337, JP-A-52-146235, JP-B-50-23813, etc.

The invention can be applied to a multilayered, multicolor photographic material having at least two light-sensitive layers having different spectral sensitivities. Multilayered color photographic materials usually comprise a support having thereon at least one red-sensitive emulsion layer, at least one green-sensitive emulsion layer and at least one blue-sensitive emulsion layer. The order of these layers can be selected as required. Usually, the red-sensitive emulsion layer is accompanied by a cyan-forming coupler, the green-sensitive emulsion layer by a magenta-forming coupler and the blue-sensitive emulsion layer by a yellow-forming coupler, although various combinations are possible in some cases.

The most preferred light-sensitive materials according to the invention are rolled color negative films for photographic use.

Known color couplers may preferably be contained in the color negative films of the invention.

That is, they may contain compounds capable of forming dyes by reaction with an oxidation product of an aromatic amine (usually primary amine) and a developing agent (hereinafter abbreviated as "coupler"). As the coupler, non-diffusible couplers having a hydrophobic group called a ballast group in the molecule may be desired. The couplers may be either of the 4-equivalent type or 2-equivalent type based on the silver ion. Colored couplers having color correction action or couplers capable of releasing a development inhibitor after development (called DIR couplers) may also be incorporated.

Known open-chain ketomethylene couplers can be used as yellow color-forming couplers. Among these, benzoylacetanilide type and pivaloylacetanilide type compounds are advantageous. Specific examples of useful yellow color forming couplers are those described in US-A-2 875 057, 3 265 506, 3 408 194, 3 551 155, 3 582 322, 3 725 072, 3 891 445, DE-C- 1 547 868, DE-A-2 219 917, 2 261 361, 2 414 006, GB-B- 1 425 020, JP-B-51-10783, JP-A-47-26133, JP-A-48-73147, JP-A- 51-102636, JP-A-50-6341, JP-A-50-123342, JP-A-50-130442, JP-A- 51-21827, JP-A-50-6341, JP-A-50-123342, JP-A-50-130442, JP-A- 51-21827, JP-A-50-87650, JP-A-52-82424, JP-A-52-115219.

As magenta color-forming couplers, pyrazolone type, indazolone type, cyanoacetyl type compounds can be used, with pyrazolone type compounds being particularly advantageous. Specific examples of useful magenta color-forming couplers are described in US-A-2,600,788, 2,983,608, 3,062,653, 3,127,269, 3,311,476, 3,419,391, 3,519,429, 3,558,319, 3 582 322, 3 615 506, 3 834 908, 3 891 445, DE-C-1 810 464, DE- A-2 408 665, 2 417 945, 2 418 959, 2 424 467, JP-B-40-6031, JP- A-51-20826, JP-A-52-58922, JP-A-49-129538, JP-A-49-74027, JP-A- 50-159336, JP-A-52-42121, JP-A-49-74028, JP-A-50-60233, JP-A- 51-26541, JP-A-53-55122.

Phenolic compounds and naphtholic compounds can be used as cyan color-forming couplers. Specific examples are those described in US-A-2 369 929, 2 434 272, 2 474 293, 2 521 908, 2 895 826, 3 034 892, 3 311 476, 3 458 315, 3 476 563, 3 583 971, 3 591 383, 3 767 411, 4 004 929, DE-A-2 414 830 and 2 454 329, JP-A-48-59838, JP-A- 51-26034, JP-A-48-5055, JP-A-51-146828, JP-A-52-69624, JP-A-52- 90932.

As colored couplers, those described, for example, in US-A-3 476 560, 2 521 903, 3 034 892, JP-B-44-2016, JP-B-38-22335, JP-B-42-11304, JP-B-44-32461, JP-A-51- 26034, JP-A-52-42121, DE-A-2 418 959 can be used.

DIR couplers which can be used are those described, for example, in US-A-3 227 554, 3 617 291, 3 701 783, 3 790 384, 3 632 345, DE-A-2 414 006, 2 454 301, 2 454 329, GB-B-953 454, JP-A-52-69624, JP-A-49-122335, JP-B-51-16141.

Compounds capable of releasing a development inhibitor after development can be incorporated into the light-sensitive material in addition to the DIR couplers, and those described in US-A-3,297,445, 3,379,529, DE-A-241,794, JP-A-52-15271, JP-A-53-9116 can be used.

The couplers described above may be used in combinations of two or more in one and the same layer, or the same compound may be used in two or more different layers.

These couplers are added to a photographic emulsion layer in an amount of 2 x 10⁻³ mol to 5 x 10⁻¹ mol, preferably 1 x 10⁻² mol to 5 x 10-1 mol, per mol of silver contained in the emulsion layer.

Couplers can be introduced into the silver halide emulsion layers in a known manner, for example as described in US-A-2 322 027. For example, they are dissolved in an alkyl phthalate (e.g., dibutyl phthalate or dioctyl phthalate), a phosphoric acid ester (e.g., diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, dioctyl butyl phosphate), a citric acid ester (e.g., tributyl acetyl citrate), a benzoic acid ester (e.g., octyl benzoate), an alkylamide (e.g., diethyl laurylamide), a fatty acid ester (e.g., dibutoxyethyl succinate or dioctyl azelate), or an organic solvent having a boiling point of about 30°C to 150°C such as a lower alkyl acetate (e.g., ethyl acetate or butyl acetate), ethyl propionate, sec-butyl alcohol, methyl isobutyl ketone, β-ethoxyethyl acetate, methyl cellusolve or the like, and the resulting solution is dispersed in a hydrophilic colloid. The high-boiling organic solvent and the low-boiling organic solvent described above may be mixed for use.

A dispersion process using a polymer described in JP-B-51-39853 and JP-A-51-59943 can also be used.

With couplers having an acid group such as a carboxylic acid or sulfonic acid group, they are introduced into a hydrophilic colloid as an alkaline aqueous solution.

The light-sensitive material prepared according to the invention may contain in its hydrophilic colloidal layer an absorbing agent for ultraviolet rays. For example, aryl group-substituted benzotriazole compounds (for example, those described in US-A-3,533,794), 4-thiazolidone compounds (for example, those described in US-A-3,314,794 and 3,352,681), benzophenone compounds (for example, those described in JP-A-46-2784), cinnamic acid esters (for example, those described in US-A-3,705,805 and 3,707,375), butadiene compounds (for example, those described in US-A-4,045,229) or benzoxazole compounds (for example, those described in US-A-3,700,455) can be used. Furthermore, those described in US-A-3,499,762 and JP-A-54-48535 can be used. Ultraviolet ray absorbing couplers (e.g., α-naphthol cyan dye-forming couplers) or ultraviolet ray absorbing polymers can also be used. These ultraviolet ray absorbing agents can be fixed to a specific layer or layers.

In photographically processing the light-sensitive material of the present invention, any known method can be used. The processing temperature is usually selected between 18°C and 50°C. However, temperatures lower than 18°C or higher than 50°C can be used.

Any development processing to form silver images only (black-and-white photographic processing) or color photographic processing comprising development processing to form a color image may be used depending on the end use.

Color developers generally comprise an alkaline aqueous solution containing a color developing agent. As the color developing agent, known primary aromatic amines such as phenylenediamine (for example 4-amino-N,N-diethylaniline, 3-methyl-4-amino-N, N-diethylaniline, 4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methanesulfonamidoethylaniline, 4-amino-3-methyl-N-ethyl-N-β-methoxyethylaniline) can be used.

In addition, those described in LFA Mason, Photographic Processing Chemistry (Focal Press, 1966), pages 226 to 229, US-A-2 193 015, 2 592 364, JP-A-48-64933 can also be used.

The developer may further contain pH buffers such as alkali metal sulfites, carbonates, borates and phosphates, development inhibitors or antifoggants such as bromides, iodides and organic antifoggants and, if necessary, water softeners, preservatives such as hydroxylamine, organic solvents such as benzyl alcohol and diethylene glycol, development accelerators such as polyethylene glycol, quaternary ammonium salts and amines, dye-forming couplers, competing couplers, fogging agents such as sodium borohydride, auxiliary developing agents such as 1-phenyl-3-pyrazolidone, agents for imparting viscosity, chelating agents of the polycarboxylic acid type described in US-A-4 083 723, antioxidants described in DE-A-2 622 950.

Color-developed photographic emulsion layers are usually bleached. Bleaching can be carried out separately or simultaneously with fixing. Compounds of polyvalent metals such as iron(III), cobalt(III), chromium(VI), copper(II), etc., peracids, quinones, nitroso compounds are used as bleaching agents. For example, ferricyanides, dichromates, organic complex salts of iron(III) or cobalt(III), such as complex salts of aminopolycarboxylic acids (for example ethylenediaminetetraacetic acid, nitrilotriacetic acid, 1,3-diamino-2-propanoltetraacetic acid) or organic acids (for example citric acid, tartaric acid, maleic acid); persulfates and permanganates; nitrosophenol. Couplers of the invention exhibit a high color-forming ability even in a bleaching solution or bleach-fixing solution containing ferric sodium ethylenediaminetetraacetate or ferric ammonium ethylenediaminetetraacetate, and thus are also advantageous in this respect.

Iron(III) ethylenediaminetetraacetate complex salts are useful in both an independent bleaching solution and a one-bath bleach-fixing solution.

To the bleaching or bleach-fixing solution, various additives such as bleach accelerators described in US-A-3,042,520, 3,241,966, JP-B-45-8506, JP-B-8836, and thiol compounds described in JP-A-53-65732 may be added.

The invention will now be illustrated in more detail by reference to the following examples, which, however, are not intended to limit the invention in any way. Unless otherwise indicated, all percentages and ratios are by weight.

EXAMPLE 1 (1) Production of polyester film

0.1 part by weight of calcium acetate monohydrate and 0.03 part by weight of antimony trioxide were added to 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 10 parts by weight of dimethyl-5-sodium sulfoisophthalate and 10 parts by weight of dimethyl adipate in a reactor equipped with a fractionating column, and an ester exchange reaction was carried out by gradually heating and removing the methanol formed. After the temperature reached 230°C, the reaction was continued at this temperature until 38 parts by weight of methanol was distilled off. 0.05 part by weight of trimethyl phosphate were added to the resulting product, and the mixture was transferred to a reactor equipped with a pressure reducing device, and the temperature was gradually raised to finally 280°C and the pressure was gradually reduced to finally not more than 1 mmHg to carry out polymerization. Thus, copolymerized PET was obtained after 3 hours from the start of the pressure reduction. The inherent viscosity of the copolymerized PET was 0.65 as measured in o-chlorophenol at 25°C.

The resulting copolymerized PET was dried at 130°C for 5 hours, then melt-extruded at 280°C to obtain a non-stretched film. The film was then successively stretched in the longitudinal direction at 90°C at a stretch ratio of 3.5 times and then in the transverse direction at 95°C at a stretch ratio of 3.7 times, and heat-set at 200°C for 5 seconds to obtain a 50 µm-thick biaxially stretched film. This film had a haze of 1.2%, a breaking strength of 12 kg/mm and an initial modulus of 340 kg/mm, and had good transparency as well as good mechanical properties.

In addition, the transparency, fracture toughness and initial modulus were measured under the following conditions.

Transparency:

The haze of a sample film was measured according to ASTM D1003-52 after heat treating the film at a temperature of 150ºC for 10 minutes.

Ultimate strength and initial modulus:

A specimen of 10 mm width and 100 mm length was subjected to measurement according to JIS Z1702-1976 using a pulling rate of 300 mm/min to measure the breaking strength and 20 mm/min to measure the initial modulus.

(2) Measurement of the curl erasure ratio:

The polyester film (50 µm thick) according to the invention was prepared as described above, and a commercially available PET film (50 µm thick) and a commercially available TAC film (125 µm thick) were subjected to measurement for water content according to the method in the invention.

Furthermore, the curl erasure ratio was measured in the manner described below to obtain the results shown in Table 1.

Method for evaluating the degree of curl erasure

A sample film measuring 12 cm x 35 cm was wound around a core of 10 mm diameter and subjected to treatment at 60ºC x 30% RH x 72 h. Then, the film was unwound from the core (roll), immersed in distilled water at 40ºC for 15 minutes and dried in a thermostatic air chamber at 55ºC for 3 minutes while applying a load of 50 g. The length of the thus-treated sample was measured in a vertically suspended state to determine the degree of recovery to the original length of 12 cm. TABLE 1 Sample Water content (wt.%) Immersion treatment Curl quenching ratio TAC (125 µm) PET (50 µm) Invention (50 µm) Treated Not treated

As can be seen from Table 1, the polyester film of the present invention having a water content of 0.5 wt.% exhibits an extremely large curl erasure ratio.

(3) Preparation of the photographic light-sensitive material (3-1) Coating the base layer:

An undercoat layer having the following formulation was coated on each of the above-mentioned polyester films and commercially available PET films after corona discharge treatment on both sides. The corona discharge treatment was carried out at a level of 0.02 KVA min/m².

Gelatine 3g

Distilled water 250 cm³

Sodium sulfodi-2-ethylhexylsuccinate 0.05 g

Formaldehyde 0.02 g

(3-2) Coating the back layer:

A backcoat of the following formulation was applied to one side of the undercoated polyester films.

Preparation of a dispersion of tin oxide-antimony oxide composite

230 parts by weight of tin chlorohydrate and 23 parts by weight of antimony trichloride were dissolved in 3,000 parts by weight of ethanol to obtain a uniform solution. A 1N aqueous solution of sodium hydroxide was added dropwise to the solution until the pH of the solution became 3 to obtain a coprecipitate of colloidal tin oxide and antimony oxide. The coprecipitate thus obtained was allowed to stand at 50°C for 24 hours to obtain a reddish brown colloidal precipitate.

The reddish brown colloidal precipitate was separated by centrifugation. To remove excess ions, water was added to the precipitate, followed by centrifugation and washing with water. This washing procedure was repeated three times to remove excess ions.

200 parts by weight of the colloidal precipitate freed of excess ions was again dispersed in 1,500 parts by weight of water and sprayed into a sintering furnace heated to 600°C to obtain a fine powder of a bluish tin oxide-antimony oxide composite having an average particle size of 0.2 mm. This fine powder had a specific resistance of 25 Ω cm.

A mixture of 40 parts by weight of the above-described fine powder and 60 parts by weight of water was adjusted to a pH of 7.0, and after being roughly dispersed with a stirrer, the mixture was dispersed with a horizontal sand mill (trade name: Dyno Mill, manufactured by WILLY A. BACHOFEN AG) until a residence time became 30 minutes.

Coating the back layer

The formulation (A) shown below was coated to a dry thickness of 0.3 µm and dried at 130ºC for 30 seconds. The coating solution (B) shown below was coated to a dry thickness of 0.1 µm and dried at 130ºC for 2 minutes. Formulation (A): Parts by weight Conductive fine particle dispersion Gelatin Water Methanol Resorcinol Polyoxyethylene nonylphenyl ether Coating solution (B) for forming the coating layer Parts by weight Cellulose triacetate Acetone Methanol Dichloromethylene p-chlorophenol

(3-3) Coating the photographic layers:

The photographic layers described below were applied to the side opposite the backcoated side of the PET film.

First layer: Red-sensitive silver halide layer with low sensitivity (1-a) Preparation of an emulsion solution for forming a low-sensitivity emulsion layer

A silver bromoiodide emulsion containing 6 mol% of iodide (average grain size 0.6 µm; containing 100 g of silver halide and 70 g of gelatin per kg of the emulsion) was prepared in a usual manner. To 1 kg of this emulsion was added 180 cc of a 0.1 wt% methanolic solution of anhydro-5,5'-dichloro-9-ethyl-3,3'-di(3-sulfpropyl)thiacarbocyanine hydroxide pyridinium salt as a red-sensitive sensitizer. Then 20 cc of a 5 wt% aqueous solution of 5-methyl-7-hydroxy-2,3,4-triazaindolizine, 330 g of cyan coupler emulsion (1) having the following formulation and 20 g of emulsion (2). Further, 50 cc of a 2% aqueous solution of 2-hydroxy-4,6-dichlorotraizine sodium salt was added as a gelatin hardening agent to prepare an emulsion to form a low-sensitivity emulsion.

emulsions (1)

(i) Aqueous 10 wt% gelatin solution 1000 g

(ii) Sodium p-dodecylbenzenesulfonate 5 g

Tricresyl phosphate 60 cm³

Cyan coupler (C-7) 70 g

Ethyl acetate 100 cm³

A mixture of (ii) was transferred to a solution at 55°C and the resulting solution was added to (i) which had previously been heated to 55°C and subsequently emulsified in a colloid mill. Cyan coupler (C-7):

emulsions (2)

(i) Aqueous 10 wt% gelatin solution 1000 g

(ii) Sodium p-dodecylbenzenesulfonate 5 g

Tricresyl phosphate 60 cm³

Cyan coupler (C-7) 6 g

DIR cyan coupler* 64 g

Ethyl acetate 100 cm³ * DIR cyan coupler

Second layer: Red-sensitive silver halide layer with medium sensitivity (1-b) Preparation of an emulsion solution for forming the medium sensitivity emulsion layer

The following changes were made to (1-a) described above.

Average grain size of the emulsion: 0.9 um

Amount of red-sensitive sensitizer added: 140 cm³

Amount of emulsion added: Emulsion (1) 240 g

Emulsion (3) 10g

Third layer: Red-sensitive silver halide layer with high sensitivity (1-c) Preparation of an emulsion solution for forming an emulsion layer with high sensitivity

The following changes were made to (1-a).

Average grain size of the emulsion: 1.1 µm (grains of 1.0 µm or larger contribute to 50 wt.% of the total grains)

Amount of red-sensitive sensitizer added: 100 cm³

Amount of emulsion added: Emulsion (1) 150 g

Fourth layer: gelatin interlayer Fifth layer: Green-sensitive silver halide layer with low sensitivity (2-a) Preparation of an emulsion solution for forming a low-sensitivity emulsion

A silver bromoiodide emulsion containing 6 mol% iodide (average grain size 0.6 µm; containing 100 g silver halide and 70 g gelatin per kg emulsion) was prepared in a conventional manner. To 1 kg of this emulsion were added 200 cm³ of a 0.1 wt% methanol solution of 3,3'-di(3-sulfoethyl)- 9-ethylbenzoxacarbocyaninepyridinium salt was added as a green sensitive sensitizer.

Then, 20 cm3 of an aqueous 5 wt% solution of 5-methyl-7-hydroxy-2,3,4-triazaindolizine were added and 380 g of magnetic coupler emulsion (3) and 20 g of magenta coupler emulsion (4) of the following formulations were added.

Further, 50 cc of a 2 wt% aqueous solution of 2-hydroxy-4,6-dichlorotriazine sodium salt was added as a gelatin hardening agent to prepare an emulsion solution for forming a low-sensitivity emulsion.

Emulsions (3)

(i) Aqueous 10 wt% gelatin solution 1000 g

(ii) Sodium p-dodecylbenzenesulfonate 5 g

Tricresyl phosphate 65 cm³

Magenta coupler (M-7) 6 g

Ethyl acetate 110 cm³

A mixture of (ii) was converted into a solution at 55°C and the resulting solution was added to (i) which had previously been heated to 55°C, followed by emulsification in a colloid mill.

Magenta coupler (M-7) 1-(2,4,6-Trichlorophenyl)-3-[3-(2,4-di-t-pentylphenoxyacetamide)benzamido]-5-pyrazolone Emulsions (4)

(i) Aqueous 10 wt% gelatin solution 1000 g

(ii) Sodium p-dodecylbenzenesulfonate 5 g

Tricresyl phosphate 65 cm³

Magenta coupler (M-7) 63 g

r** 60 g

Ethyl acetate 110 cm³

Emulsification was carried out in the same manner as with emulsion (3).

** DIR-Magenta coupler 1-{4-[2-((2,4-Di-t-pentylphenoxy)butamide]phenyl}-3-(1-pyrrolidinyl)-4-(1-phenyltetrazolyl-5-thio)-5-pyrazolone *Magenta coupler Sixth layer: Green-sensitive silver halide layer with medium sensitivity (2-b) Preparation of an emulsion solution for forming an emulsion layer with medium sensitivity

A silver bromide emulsion containing 5 mol% of iodide (average grain size: 0.9 µm; containing 100 g of silver halide and 70 g of gelatin per kg of the emulsion) was prepared in a conventional manner. To 1 kg of the emulsion was added 150 cm³ of a methanol solution of the green-sensitive sensitizer shown in (2-a). Then, 20 cm³ of an aqueous 5 wt% solution of 5-methyl-7- hydroxy-2,3,4-triazaindolizine was added. Furthermore, 285 g of the emulsion (3) described above and 15 g of the emulsion (4) described above were added.

In addition, 50 cc of a 2 wt% aqueous solution of 2-hydroxy-4,6-dichlorotriazine sodium salt was added as a gelatin hardening agent to prepare an emulsion solution for forming a medium-sensitivity emulsion.

Seventh layer: Green-sensitive silver halide layer with high sensitivity (2-c) Preparation of an emulsion solution for forming an emulsion layer with high sensitivity

A silver bromoiodide emulsion containing 6 mol% of iodide (average grain size 1.1 µm; 50 wt% of the grains based on the total grains have a grain size of 1.0 µm or more; containing 100 g of silver halide and 70 g of gelatin per kg of the emulsion) was prepared in a conventional manner. To 1 kg of this emulsion was added 80 cc of a methanol solution of the green-sensitive sensitizer shown in (2-a). Then 20 cc of an aqueous 5 wt% solution of 5-methyl-7-hydroxy-2,3,4-triazaindolizine was added, and further 200 g of the emulsion (3) was added.

50 cm³ of an aqueous 2 wt% solution of 2-hydroxy-4,6-dichlorotriazine sodium salt was further added as a gelatin hardening agent to prepare an emulsion solution for forming a high-sensitivity emulsion.

Eighth layer: Yellow filter layer (dry thickness: 1.2 µm) comprising yellow colloidal silver Ninth layer: Blue-sensitive silver halide layer with low sensitivity (3-a) Preparation of an emulsion solution for forming a low-sensitivity emulsion layer

A silver bromoiodide emulsion containing 5 mol% of iodide (average grain size 0.6 µm; containing 100 g of silver halide and 70 g of gelatin per kg of emulsion) was prepared in a conventional manner. To 1 kg of this emulsion was added 20 cm³ of an aqueous 5 wt% solution of 5-methyl-7-hydroxy-2,3,4-triazaindolizine and 600 g of yellow coupler emulsion (5) of the following formulation.

Emulsions 5

(i) Aqueous 10 wt% gelatin solution 1000 g

(ii) Sodium p-dodecylbenzenesulfonate 5 g

Tricresyl phosphate 80 cm³

Yellow coupler* 100 g

Yellow DIR Coupler** 10 g

Ethyl acetate 120 cm³ * Yellow coupler: ** Yellow DIR coupler

Tenth layer: Blue-sensitive silver halide layer with medium sensitivity

The following changes were made to (3-a) above.

Average grain size of the emulsion: 0.9 um

Amount of emulsion added: 400 g

Eleventh layer: Blue-sensitive silver halide layer with high sensitivity

The following changes were made to (3-a) above.

Average grain size of the emulsion: 1.1 µm (provided that the grains larger than 1.0 µm constitute 50 wt.% of the total grains).

Amount of emulsion added: 200 g

Twelfth layer: surface protection layer

Aqueous 10 wt.% gelatin solution 1000 g

Sodium dodecylbenzenesulfonate 40 mg

Fine SiO2 particles (3.0 µm) 50 mg

Sodium polystyrene sulfonate 1 g

2-Hydroxy-4,6-dichlorotriazine 50 mg

In addition, the amounts of coated silver for the respective photosensitive layers described above were: first layer (1.0 g/m²); second layer (0.8 g/m²); third layer (1.2 g/m²); fifth layer (1.2 g/m²); sixth layer (1.0 g/m²); seventh layer (1.2 g/m²); ninth layer (0.6 g/m²); tenth layer (0.6 g/m²) and eleventh layer (0.6 g/m²).

The color negative film thus obtained was cut into 35 mm size and loaded into a cartridge. After remaining at 40ºC for 10 days, it was photographed with an ordinary camera and then the film was subjected to development treatment as follows. Treatment step Temperature (ºC) Time (min) Colour development Stop Washing with water Bleaching Fixing Stabilising bath

The treatment solutions used had the following formulations.

Color developer:

Sodium hydroxide 2 g

Sodium sulphite 2 g

Potassium bromide 0.4 g

Sodium chloride 1 g

Borax 4g

Hydroxylamine sulphate 2 g

Disodium ethylenediaminetetraacetate dihydrate 2 g

4-Amino-3-methyl-N-ethyl-N-β-hydroxyethyl)aniline monosulfate 4 g

Water to 1 l

Stop bath:

Sodium thiosulfate 10 g

Ammonium thiosulfate (70 wt.% aqueous solution 30 ml

Acetic acid 30 ml

Sodium acetate 5 g

Kalinit 15 g

Water to 1 l

Bleaching solution:

Iron(III) sodium ethylenediaminetetraacetate dihydrate 100 g

Potassium bromide 50 g

Ammonium nitrate 50 g

Borax 5g

Aqueous ammonia to adjust the pH to 5.0

Water to 1 l

Fixing solution:

Sodium thiosulfate 150 g

Sodium sulphite 15 g

Borax 12g

Glacial acetic acid 15 ml

Kalinit 20 g

Water to 1 l

Stabilization bath:

Borax 5g

Sodium citrate 5 g

Sodium metaborate (tetrahydrate) 3 g

Kalinit 15 g

Water to 1 l

The curling state after development processing was as follows. Photosensitive materials containing a commercially available PET film as a support were unable to erase curling properties, while photosensitive materials containing a polyester film according to the invention hardly curled.

The light-sensitive material of the present invention contains as a support a polyester film having excellent mechanical strength and enables the degradation or removal of curling properties while maintaining the mechanical properties.

COMPARISON EXAMPLE 1

A 50 µm thick biaxially stretched polyester film having an inherent viscosity of 0.67 was prepared in the same manner as in Example 1 except that 10 parts by weight of polyethylene glycol having a molecular weight of 4,000 was used in place of the same amount of dimethyl adipate. The resulting film had a haze of 4.5%, a breaking strength of 8 kg/mm², an initial modulus of 320 kg/mm² and a very weak transmittance. When this film was not subjected to heat treatment for measurement of haze, it had a high transmittance and had a haze of 2.0%.

A photosensitive material was prepared in the same manner as in Example 1 using the biaxially stretched polyester film obtained above. After development treatment, the exposed part of the film became opaque and the developed images were not sharp. From the above, it is clear that the polyester film prepared in Comparative Example 1 is not useful as a support for a light-sensitive material.

Since the photosensitive materials of the invention have excellent mechanical properties and allow easy erasure of curl, they allow a reduction in the thickness of the support even when used as roll films and therefore make the size of the cartridge compact or allow loading with a longer film when using the same cartridge. The polyester film of the invention can be produced at a low melting temperature and does not break after stretching, and despite its high water content, it retains the essential advantages of polyester films.

In addition, it suffers extremely less from precipitation of oligomers despite the high water content and thus does not suffer from adverse effects on the photographic properties.

Furthermore, it allows a reduction in moisture in rolled photosensitive materials and therefore the photographic properties change little over time.

Claims

1. A photographic light-sensitive material comprising a polyester film support having at least one silver halide light-sensitive emulsion layer disposed thereon, the polyester film having a fog of up to 3%, a water content of 0.5% by weight to 5.0% by weight, a curl erasure ratio of 50% or more, and having as predominant components a terephthalic acid component and a glycol component, the polyester film further having an aliphatic dicarboxylic acid component having 4 to 20 carbon atoms as a copolymerization component in an amount of 3 to 25 mol% based on the terephthalic acid component, wherein the fog is measured in accordance with ASTM D1003-52 after heat-treating the film at a temperature of 150°C for 10 minutes, and the water content is measured after first heating the film under the conditions of 23°C and 30% RH humidity for 3 hours, and next, the film is immersed in distilled water at 23ºC for 15 minutes, and then the water content is measured using a micro humidity meter at a drying temperature of 150ºC, and the curl erasure ratio is measured after first the film is immersed in distilled water at 40ºC for 15 minutes, and then dried for 3 minutes in air in a thermostatic chamber maintained at 55ºC using a load of 50 g.

2. The photographic light-sensitive material according to claim 1, wherein the polyester film is a polyester film containing an aromatic dicarboxylic acid having a metal sulfonate group as a copolymerization component and having a breaking strength of 8 to 25 kg/mm² and an initial modulus of 200 to 500 kg/mm².

3. A photographic light-sensitive material according to claim 1 or 2, wherein the polyester film is a copolymerized polyethylene terephthalate film.

4. The photographic light-sensitive material according to claim 2, wherein the aromatic dicarboxylic acid having a metal sulfonate group is selected from the group consisting of 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 2-potassium sulfoterephthalic acid, 2-lithium sulfoterephthalic acid, 4-sodium sulfophthalic acid, 4-potassium sulfophthalic acid, 4-lithium sulfophthalic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid, 4-potassium sulfo-2,6-naphthalenedicarboxylic acid and 4-lithium sulfo-2,6-naphthalenedicarboxylic acid.

5. The photographic light-sensitive material according to claim 2, wherein the polyester film mainly comprises terephthalic acid as a dicarboxylic acid component, and the copolymerization amount of the aromatic dicarboxylic acid component with a metal sulfonate group is 2 to 15 mol% based on the terephthalic acid component.

6. A photographic light-sensitive material according to claim 1, wherein the aliphatic dicarboxylic acid component is selected from the group consisting of succinic acid, adipic acid and sebacic acid.

7. A photographic light-sensitive material according to claim 1, wherein a polyalkylene glycol is used as an additional copolymerizable component.

8. A photographic light-sensitive material according to claim 3, wherein the polyester film contains a dye.

9. A photographic light-sensitive material according to claim 3, wherein the polyester film carries an undercoat layer on its surface.

10. A photographic light-sensitive material according to claim 1, wherein the light-sensitive material is a roll film.

11. The photographic light-sensitive material according to claim 1, wherein the polyester film has a curl erasure ratio of 80% or more.

12. A photographic light-sensitive material according to claim 1 or 2, wherein the polyester film has a thickness of 25 to 250 µm.

13. A photographic light-sensitive material according to claim 12, wherein the polyester film has a thickness of 40 to 150 µm.